The need for effective therapeutic treatment of patients has resulted in the development of a variety of pharmaceutical composition delivery techniques. Administration of a drug or drug combination in form of a solution or a suspension is often desirable. Degradation of active agents can often occur in solutions or suspensions. As a result, many pharmaceutical formulations are restricted in the manner of their delivery, which may make them unsuitable for young children and other patients. Some solution or suspension formulations must be administered within minutes after opening the formulation's container, and any unused portion must be discarded after this time. Other formulations must be administered with a carrier, for example a small selection of soft foods. Such restrictions can lead to reduced patient compliance as well as wasted medication.
In other cases, although a particular drug may be chemically stable in water, liquid formulations such as aqueous solutions and suspensions for oral administration are not used because of the unpalatatability of the particular drug. Unpalatable drugs which are carried in aqueous media are tasted almost immediately upon ingestion and produce an unpleasant taste or after-taste. For example, the antibiotics clarithromycin and erythromycin are valuable therapeutic agents for treating infections and are somewhat unpalatable.
Additional problems resulting in poor shelf life which can occur in liquid formulations include particle agglomeration, stratification, and caking upon standing.
There is thus a need in the pharmaceutical formulation arts for stable drug formulations which can be administered in the form of an aqueous solution or suspension.